The 31-year-old former QPR full-back has joined the Bluebirds on a free transfer from Watford.
However, it was because of his time spent with Burton at Wimbledon and Watford that Darlington decided to link up with the capital outfit.
"As soon as Terry contacted me about coming to Cardiff my mind was made up," said Darlington.
"He was the manager at Watford in my first year there when we played some really good football and almost made the old Division One play-offs."